/**
 *    Copyright ${license.git.copyrightYears} the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.mybatis.generator.internal.util;

import static org.mybatis.generator.internal.util.messages.Messages.getString;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.List;

/**
 * This class holds methods useful for constructing custom classloaders.
 * 
 * @author Jeff Butler
 * 
 */
public class ClassloaderUtility {

  /**
   * Utility Class - No Instances
   */
  private ClassloaderUtility() {
  }

  public static ClassLoader getCustomClassloader(List<String> entries) {
    List<URL> urls = new ArrayList<URL>();
    File file;

    if (entries != null) {
      for (String classPathEntry : entries) {
        file = new File(classPathEntry);
        if (!file.exists()) {
          throw new RuntimeException(getString("RuntimeError.9", classPathEntry)); //$NON-NLS-1$
        }

        try {
          urls.add(file.toURI().toURL());
        } catch (MalformedURLException e) {
          // this shouldn't happen, but just in case...
          throw new RuntimeException(getString("RuntimeError.9", classPathEntry)); //$NON-NLS-1$
        }
      }
    }

    ClassLoader parent = Thread.currentThread().getContextClassLoader();

    URLClassLoader ucl = new URLClassLoader(urls.toArray(new URL[urls.size()]), parent);

    return ucl;
  }
}
